CMOS fabrication process

ABSTRACT

Ultra high temperature (UHT) anneals above 1200 C for less than 100 milliseconds for PMOS transistors reduce end of range dislocations, but are incompatible with stress memorization technique (SMT) layers used to enhance NMOS on-state current. This invention reverses the conventional order of forming the NMOS first by forming PSD using carbon co-implants and UHT annealing them before implanting the NSD and depositing the SMT layer. End of range dislocation densities in the PSD space charge region below 100 cm −2  are achieved. Tensile stress in the PMOS from the SMT layer is significantly reduced. The PLDD may also be UHT annealed to reduce end of range dislocations close to the PMOS channel.

FIELD OF THE INVENTION

This invention relates to the field of CMOS integrated circuits. Moreparticularly, this invention relates to methods to improve p-channel MOStransistor performance.

BACKGROUND OF THE INVENTION

It is well known that lateral dimensions of n-channel metal oxidesemiconductor (NMOS) and p-channel metal oxide semiconductor (PMOS)transistors in complementary metal oxide semiconductor (CMOS) integratedcircuits (ICs) are shrinking in time with each new fabricationtechnology node, as articulated by Moore's Law. P-type source and drain(PSD) regions in PMOS transistors are typically formed by ion implantingdopants and other species, producing end of range defects which causeundesirable leakage current; the relative detrimental impact of end ofrange defects increases as transistor size shrinks. Laser annealing,flash annealing and other ultra high temperature (UHT) processes whichheat surfaces of ICs over 1200 C for time periods less than 100milliseconds, when performed before other anneal processes, havedemonstrated significant reductions of end of range defects. Rapidthermal processing (RTP) methods, such as spike anneals, which heat ICsfor time periods longer than 1 second, are not as effective at reducingend of range defects due to the necessarily lower temperatures used.Increasing temperatures above 1200 C in a rapid thermal anneal processto annihilate end of range defects would produce unacceptably highspreads in spatial distributions of boron dopants in the PSD regions.Boron has a higher diffusivity than commonly used n-type dopants, sotypical CMOS IC fabrication process sequences form n-type source anddrain (NSD) regions in NMOS transistors before PSD regions to minimizethe thermal profile on the implanted dopants in the PSD regions.

NMOS transistors in advanced CMOS ICs are frequently enhanced by aprocess sequence known as stress memorization technique (SMT), in whicha layer of tensile material is deposited on an IC after the NSD ionimplantation process is performed and before a subsequent annealprocess. During the anneal, the polycrystalline silicon (polysilicon) inthe NMOS gate, which was partially amorphized by the NSD ion implants,recrystallizes with a grain configuration that exerts stress on theunderlying NMOS channel when the tensile material layer is removed. Theresultant strain in the NMOS channel increases the mobility of chargecarriers, which desirably improves the on-state current. UHT processesare incompatible with SMT processes for several reasons: UHT annealingbefore deposition of the tensile layer causes recrystallization of thepolysilicon in the NMOS gate, greatly reducing the SMT effect, while UHTannealing after deposition of the SMT layer hardens the SMT layer to thepoint of making removal problematic.

SUMMARY OF THE INVENTION

This Summary is provided to comply with 37 C.F.R. §1.73, requiring asummary of the invention briefly indicating the nature and substance ofthe invention. It is submitted with the understanding that it will notbe used to interpret or limit the scope or meaning of the claims.

The instant invention provides a method of forming a CMOS IC in whichp-type source and drain (PSD) regions of PMOS transistors are formedbefore n-type source and drain (NSD) regions of NMOS transistors, inwhich the PSD regions are implanted with a pre-amorphization implant(PAI) and a carbon species co-implant and annealed with an ultra hightemperature (UHT) process above 1200 C for less than 100 milliseconds,and in which tensile stress is applied to the NMOS gate by a stressmemorization technique (SMT) layer which is deposited after the PSD UHTanneal. Optionally, p-type lightly doped drain (PLDD) regions may beannealed with a UHT process.

DESCRIPTION OF THE VIEWS OF THE DRAWING

FIG. 1A through FIG. 1H are cross-sections of a CMOS IC duringsuccessive stages of fabrication of a PMOS transistor formed accordingto an embodiment of the instant invention.

DETAILED DESCRIPTION

The present invention is described with reference to the attachedfigures, wherein like reference numerals are used throughout the figuresto designate similar or equivalent elements. The figures are not drawnto scale and they are provided merely to illustrate the invention.Several aspects of the invention are described below with reference toexample applications for illustration. It should be understood thatnumerous specific details, relationships, and methods are set forth toprovide a full understanding of the invention. One skilled in therelevant art, however, will readily recognize that the invention can bepracticed without one or more of the specific details or with othermethods. In other instances, well-known structures or operations are notshown in detail to avoid obscuring the invention. The present inventionis not limited by the illustrated ordering of acts or events, as someacts may occur in different orders and/or concurrently with other actsor events. Furthermore, not all illustrated acts or events are requiredto implement a methodology in accordance with the present invention.

For the purposes of this disclosure, the term “implant” will beunderstood to mean “ion implant.”

The need for a p-channel metal oxide semiconductor (PMOS) transistorwith reduced end of range defects integrated into a complementary metaloxide semiconductor (CMOS) integrated circuit (IC) with an n-channelmetal oxide semiconductor (NMOS) transistor fabricated with a stressmemorization technique (SMT) process sequence is addressed by theinstant invention, which provides a PMOS transistor in which p-typesource and drain (PSD) regions are formed before n-type source and drain(NSD) regions are formed in the NMOS transistor, a pre-amorphizationimplant (PAI) process and a carbon co-implant process are used to formthe PSD regions, and an ultra high temperature (UHT) anneal process,which heats the PSD regions above 1200 C for less than 100 milliseconds,is performed after the PSD implants and before an SMT layer isdeposited.

FIG. 1A through FIG. 1H are cross-sections of a CMOS IC duringsuccessive stages of fabrication of a PMOS transistor formed accordingto an embodiment of the instant invention. Referring to FIG. 1A, theCMOS IC (100) is fabricated on a substrate (102), typically a singlecrystal silicon wafer with a p-type top layer having an electricalresistivity of 1 to 100 ohm-cm, but possibly a silicon-on-insulator(SOI) wafer, a hybrid orientation technology (HOT) wafer with regions ofdifferent crystal orientation, or any other substrate suitable forfabricating a CMOS IC. Elements of field oxide (104) are formed by ashallow trench isolation (STI) process sequence, in which trenches,commonly 200 to 500 nanometers deep, are etched into the CMOS IC (100),electrically passivated, commonly by growing a thermal oxide layer onsidewalls of the trenches, and filled with insulating material,typically silicon dioxide, commonly by a high density plasma (HDP)process or an ozone based thermal chemical vapor deposition (CVD)process, also known as the high aspect ratio process (HARP). A p-typewell (106), commonly called a p-well, is formed in the substrate (102),typically by ion implanting a first set of p-type dopants, includingboron, possibly in the form of BF₂, and possibly gallium and/or indium,at doses from 1·10¹¹ to 1·10¹⁴ atoms/cm², into a region defined for anNMOS transistor. A p-well photoresist pattern, not shown in FIG. 1A forclarity, is commonly used to block the first set of p-type dopants fromregions defined for PMOS transistors. The p-well (106) extends from atop surface of the substrate (102) to a depth typically 50 to 500nanometers below a bottom surface of the field oxide elements (104). Theion implantation process to form the p-well (106) may include additionalsteps to implant additional p-type dopants at shallower depths forpurposes of improving NMOS transistor performance, such as thresholdadjustment, leakage current reduction and suppression of parasiticbipolar operation. Similarly, an n-type well (108), commonly called ann-well, is formed in the substrate (102), typically by ion implanting afirst set of n-type dopants, including phosphorus and arsenic, andpossibly antimony, at doses from 1·10¹¹ to 1·10¹⁴ atoms/cm², into aregion defined for the inventive PMOS transistor. An n-well photoresistpattern, not shown in FIG. 1A for clarity, is commonly used to block thefirst set of n-type dopants from regions defined for NMOS transistors.The n-well (108) extends from the top surface of the substrate (102) toa depth typically 50 to 500 nanometers below the bottom surface of thefield oxide elements (104). The ion implantation process to form then-well (108) may include additional steps to implant additional n-typedopants at shallower depths for purposes of improving PMOS transistorperformance, such as threshold adjustment, leakage current reduction andsuppression of parasitic bipolar operation. A sheet resistivity of then-well (108) is commonly between 100 and 1000 ohms/square.

Still referring to FIG. 1A, a gate dielectric layer (110) typicallysilicon dioxide, nitrogen doped silicon dioxide, silicon oxy-nitride,hafnium oxide, layers of silicon dioxide and silicon nitride, or otherinsulating material, commonly 1 to 3 nanometers thick, is formed on thetop surface of the substrate (102). It is common to use the gatedielectric layer (110) in regions defined for NMOS transistors and inregions defined for PMOS transistors. An NMOS gate (112) and a PMOS gate(114), typically polycrystalline silicon, commonly called polysilicon,and typically 50 to 150 nanometers thick, are formed on a top surface ofthe gate dielectric layer (110), by deposition of a polysilicon layer onthe top surface of the gate dielectric layer (110), formation of a gatephotoresist pattern by known photolithographic methods on a top surfaceof the polysilicon layer to define the NMOS and PMOS gate regions, andremoval of unwanted polysilicon by known etching methods. Typicalminimum widths of NMOS gates and PMOS gates, commonly called minimumgate lengths, in advanced CMOS ICs are less than 40 nanometers.

Continuing to refer to FIG. 1A, NMOS offset spacers (116), commonlysilicon dioxide or silicon nitride, or both, typically 1 to 10nanometers thick, are formed on lateral surfaces of the NMOS gate (112),typically by oxidizing exposed surfaces of the NMOS gate (112) and/ordepositing a layer of silicon dioxide or silicon nitride on the CMOS IC(100) followed by anisotropic etchback using known etching methods.N-type lightly doped drain (NLDD) regions (118) are formed by ionimplanting a second set of n-type dopants, typically phosphorus andarsenic, and possibly antimony, at doses from 1·10¹⁴ to 5·10¹⁵atoms/cm², at energies from 2 to 20 keV, into the substrate (102)adjacent to the NMOS offset spacers (116). P-type NMOS pocket or haloregions (120) are formed by ion implanting a second set of p-typedopants, typically boron, possibly in the form of BF₂, and possiblygallium and/or indium, at doses from 1·10¹² to 1·10¹⁴ atoms/cm², atenergies from 10 to 40 keV, commonly divided into subdoses and angled at15 to 30 degrees about a vertical axis to provide uniform doping on allsides of an NMOS gate, into the substrate (102) between the NLDD regions(118) and a channel region immediately below the gate dielectric layer(110) under the NMOS gate (112). An NLDD photoresist pattern, not shownin FIG. 1A for clarity, is typically used to block the second set ofn-type dopants and second set of p-type dopants from regions defined forPMOS transistors.

Still referring to FIG. 1A, PMOS offset spacers (122), commonly silicondioxide or silicon nitride, or both, typically 1 to 10 nanometers thick,are formed on lateral surfaces of the PMOS gate (114), typically byoxidizing exposed surfaces of the NMOS gate (114) and/or depositing alayer of silicon dioxide or silicon nitride on the CMOS IC (100)followed by anisotropic etchback using known etching methods. Formationof p-type lightly doped drain (PLDD) regions (124) and n-type PMOSpocket or halo regions (126) proceeds by forming a PLDD photoresistpattern (128) to define regions for PLDD ion implants, which includeregions defined for PMOS transistors, by known photolithographicmethods. A series of PLDD ion implants is performed, including a PLDDPAI, preferably of indium, depicted schematically in FIG. 1A byreference numeral (130), at a dose between 1·10¹³ to 5·10¹⁴ atoms/cm², afirst subdose of a PLDD pocket implant, typically of phosphorus andarsenic, depicted schematically in FIG. 1A by reference numeral (132),at a dose between 3·10¹² to 1·10¹⁴ atoms/cm², and angled between 10 and30 degrees, a second subdose of the PLDD pocket implant, depictedschematically in FIG. 1A by reference numeral (134), a PLDD dopantimplant, typically of boron, preferably in the form of BF₂, depictedschematically in FIG. 1A by reference numeral (136), at a dose between1·10¹⁴ to 3·10¹⁵ atoms/cm², and a PLDD carbon co-implant of a carboncontaining species, depicted schematically in FIG. 1A by referencenumeral (138), at a dose between 1·10¹⁴ to 1·10¹⁵ atoms/cm². In apreferred embodiment, amorphization in the PLDD regions (124) isachieved by the combined action of the PLDD PAI and the PLDD pocketimplants. In alternate embodiments, a species implanted in the PLDD PAImay be chosen from a long list of materials, including group IV elementssuch as germanium or silicon, heavy dopant atoms such as antimony orindium, or inert gases such as argon. PLDD end of range defects (140)are formed in the substrate (102) in space charge regions of the PLDDregions (124) by the series of PLDD ion implants

FIG. 1B depicts the CMOS IC (100) during a PLDD UHT anneal process, inwhich radiant energy, depicted schematically in FIG. 1B by referencenumeral (142), from a laser, a flash light source, a microwave source,or other power source, irradiates the CMOS IC (100), raising atemperature of the PLDD regions (124) and PMOS pocket regions (126)above 1200 C for less than 100 milliseconds. A practical lower limit forthe time duration of a PLDD UHT anneal process may be placed at 50microseconds. The PLDD end of range defects are reduced below 100dislocations/cm² during the PLDD UHT anneal by a process involvingsubstitutional carbon from the carbon co-implant. The combination ofPLDD carbon co-implant and PLDD UHT anneal is advantageous because theannihilation of PLDD end of range defects using both the carbonco-implant and UHT anneal is more complete than the use of either carbonco-implant or UHT anneal alone. In particular, substitution of a rapidthermal process (RTP) anneal, which produces a lower peak temperatureand longer heating time duration, for the PLDD UHT anneal processresults in an undesirable higher density of PLDD end of range defects.

It is within the scope of the instant invention to form the PLDD regions(124) and PMOS pocket regions (126) before forming the NLDD regions(118) and NMOS pocket regions (120).

FIG. 1C depicts the CMOS IC (100) during formation of the PSD regions(144). NMOS gate sidewall spacers (146) are formed on lateral surfacesof the NMOS offset spacers (116), typically by depositing a layer orlayers of silicon dioxide, silicon nitride, or both, on the NMOS gate(112), followed by anisotropically etching the deposited layers from atop surface of the NMOS gate (112) and the top surface of the substrate(102). Similarly, PMOS gate sidewall spacers (148) are formed on lateralsurfaces of the PMOS offset spacers (122), typically by depositing alayer or layers of silicon dioxide, silicon nitride, or both, on theNMOS gate (112), followed by anisotropically etching the depositedlayers from a top surface of the PMOS gate (114) and the top surface ofthe substrate (102). A PSD photoresist pattern (150) is formed to defineregions for PSD ion implants, which include regions defined for PMOStransistors, by known photolithographic methods. A series of PSD ionimplants is performed, including a PSD dopant implant, typically ofboron, preferably in the form of BF₂, depicted schematically in FIG. 1Cby reference numeral (154), at a dose between 5·10¹⁴ to 1·10¹⁶atoms/cm², and a PSD carbon co-implant of a carbon containing species,depicted schematically in FIG. IC by reference numeral (156), at a dosebetween 1·10¹⁴ to 1·10¹⁵ atoms/cm². PSD end of range defects (158) areformed in the substrate (102) in space charge regions of the PSD regions(144) by the series of PSD ion implants

FIG. 1D depicts the CMOS IC (100) during a PSD UHT anneal process, inwhich radiant energy, depicted schematically in FIG. 1D by referencenumeral (160), from a laser, a flash light source, a microwave source,or other power source, irradiates the CMOS IC (100), raising atemperature of the PSD regions (144) above 1200 C for less than 100milliseconds. A practical lower limit for the time duration of a PSD UHTanneal process may be placed at 50 microseconds. The PSD end of rangedefects are reduced below 100 dislocations/cm² during the PSD UHT annealby a process involving substitutional carbon from the PSD carbonco-implant. The combination of PSD carbon co-implant and PSD UHT annealis advantageous because the annihilation of PSD end of range defectsusing both the carbon co-implant and UHT anneal is more complete thanthe use of either carbon co-implant or UHT anneal alone. In particular,substitution of an RTP anneal, which produces a lower peak temperatureand longer heating time duration, for the PSD UHT anneal process resultsin an undesirable higher density of PSD end of range defects.

Still referring to FIG. 1D, the PLDD regions (124) and PSD regions (144)merge during the PSD UHT anneal.

FIG. 1E depicts the CMOS IC (100) at a further stage of fabrication. NSDregions (162) are formed in the substrate adjacent to the NMOS gatesidewall spacers (146) by an NSD series of ion implants, including athird set of n-type dopants. An NSD photoresist pattern, no shown inFIG. 1E for clarity, blocks the third set of dopants from regionsdefined for PMOS transistors. A portion (164) of the NMOS gate (112) isamorphized by the NSD series of ion implants. A stress memorizationtechnique (SMT) layer (166) is formed on a top surface of the CMOS IC(100) prior to annealing the NSD regions (162). The SMT layer (166) istypically silicon nitride, 10 to 200 nanometers thick, with a tensilestress between 500 and 1500 MPa.

FIG. 1F depicts the CMOS IC (100) during an NSD RTP anneal of the NSDregions (162), in which the CMOS IC (100) is typically heated to 850 Cto 1100 C for 1 to 60 seconds by radiant energy, depicted schematicallyin FIG. 1F by reference numeral (168). The NSD regions (162) and theamorphous portion of the NMOS gate (112) are recrystallized during theNSD RTP anneal in a manner that introduces tensile stress, typicallybetween 50 and 1000 MPa, to the NMOS gate after the SMT layer (166) isremoved. The tensile stress in the NMOS gate (112) desirably increasethe NMOS transistor on-state current. Tensile stress in the PMOS gate(114) does not have desirable effects, so the process sequence of ionimplanting the PSD regions (144) and annealing them before deposition ofthe SMT layer (166) is advantageous because the tensile stress of theSMT layer (166) is not effectively transferred to the annealed PMOS gate(114). The SMT layer (166) is removed by known etching methods beforesubsequent anneal process steps.

FIG. 1G depicts the CMOS IC (100) after removal of the SMT layer, duringan optional subsequent post-NSD UHT anneal process step. Similarly toprevious UHT anneal processes, the post-NSD UHT anneal processirradiates the CMOS IC (100) with radiant energy, depicted schematicallyin FIG. 1G by reference numeral (170), from a laser, a flash lightsource, a microwave source, or other power source, raising thetemperature of the NSD and PSD regions (144, 162) above 1200 C for lessthan 100 milliseconds. More dopant atoms in the NSD regions (162) areactivated and more damage from the NSD series of ion implants isrepaired by the post-NSD UHT anneal process.

FIG. 1H depicts the CMOS IC (100) at a further stage of fabrication.Layers of metal silicide (172), typically nickel silicide, but possiblycobalt silicide, titanium silicide, or another metal silicide, areformed on top surfaces of the PSD regions (144) and NSD regions (162) toreduce electrical resistance to the PSD regions (144) and NSD regions(162), respectively. A pre-metal dielectric layer (PMD), typically adielectric layer stack including a silicon nitride or silicon dioxidePMD liner (174), 10 to 100 nanometers thick deposited by plasma enhancedchemical vapor deposition (PECVD), a layer of silicon dioxide,phospho-silicate glass (PSG) or boro-phospho-silicate glass (BPSG)(176), commonly 100 to 1000 nanometers thick deposited by PECVD,commonly leveled by a chemical-mechanical polish (CMP) process, and anoptional PMD cap layer, commonly 10 to 100 nanometers of a hard materialsuch as silicon nitride, silicon carbide nitride or silicon carbide, isformed on a top surface of the CMOS IC (100). Contacts (178) are formedin the PMD and PMD liner (174, 176) by etching contact holes in the PMDand PMD liner (174, 176) to expose the metal silicide layers (172), andfilling the contact holes with contact metal, typically tungsten, suchthat electrical connections between the contacts (178) and the metalsilicide layers (172) are formed. An intra-metal dielectric (IMD) layer(180) is formed on a top surface of the PMD (176), typically 100 to 200nanometers thick, and typically of a material commonly known as a low-kdielectric, which has a dielectric constant less than that of silicondioxide, such as organo-silicate glass (OSG), carbon-doped silicon oxide(SiCO or CDO) or methylsilsesquioxane (MSQ). Metal interconnects (182),typically copper, but possibly aluminum, are formed in the IMD layer(180) contacting top surfaces of the contacts (178). A PSD region (144)may be electrically connected to an NSD region (162) through metalsilicide layers (172), contacts (178) and a metal interconnect (182) toform a portion of a circuit in the CMOS IC (100).

1. A method of forming a complementary metal oxide semiconductor (CMOS)integrated circuit (IC), comprising the following steps, performed inthe order listed: providing a substrate; forming an n-channel metaloxide semiconductor (NMOS) gate and a p-channel metal oxidesemiconductor (PMOS) gate on said substrate; forming p-type lightlydoped drain (PLDD) regions in said substrate adjacent to said PMOS gate;forming NMOS gate sidewall spacers on lateral surfaces of said NMOS gateand PMOS gate sidewall spacers on lateral surfaces of said PMOS gate;ion implanting p-type source and drain (PSD) regions in said substrateadjacent to said PMOS gate sidewall spacers with a first set of p-typedopants and a first carbon species; performing a PSD ultra hightemperature (UHT) anneal on said PSD regions at a temperature above 1200C for a time duration between 50 microseconds and 100 milliseconds; ionimplanting n-type source and drain (NSD) regions in said substrateadjacent to said NMOS gate sidewall spacers with a first set of n-typedopants; forming a stress memorization technique (SMT) layer with 500 to1500 MPa tensile stress on said NMOS gate and said PMOS gate, whereinthe instant step is performed after said step of performing a PSD UHTanneal; performing a rapid thermal process (RTP) anneal on said CMOS ICat a temperature above 850 C; and removing said SMT layer.
 2. The methodof claim 1, in which a radiant power source used in said PSD UHT annealis a laser.
 3. The method of claim 1, in which a radiant power sourceused in said PSD UHT anneal is a flash illuminator.
 4. The method ofclaim 1, in which said step of performing a PSD UHT anneal reduces adensity of dislocation in space charge regions of said PSD regions below100 dislocations/cm².
 5. The method of claim 4, in which said step offorming PLDD regions further comprises the following steps, performed inthe order listed: ion implanting said PLDD regions with apre-amorphization implant (PAI) and a second carbon species; andperforming a PLDD ultra high temperature (UHT) anneal on said PLDDregions at a temperature above 1200 C for a time duration between 50microseconds and 100 milliseconds.
 6. The method of claim 5, in whichsaid PAI further comprises implanting indium at a dose between 1·10¹³and 5·10¹⁴ atoms/cm².
 7. The method of claim 6, in which said step ofperforming a PLDD UHT anneal reduces a density of dislocation in spacecharge regions of said PLDD regions below 100 dislocations/cm².
 8. Themethod of claim 7, further comprising the steps of; forming metalsilicide layers on top surfaces of said NSD regions and said PSDregions; forming a pre-metal dielectric (PMD) liner on top surfaces ofsaid metal silicide layers; forming a PMD layer on a top surface of saidPMD liner; forming contacts in said PMD and said PMD liner which makeelectrical connections with said metal silicide layers; forming anintra-metal dielectric (IMD) layer on a top surface of said PMD; andforming a set of metal interconnects in said IMD layer which makeelectrical connections to said contacts.
 9. A method of forming a PMOStransistor, comprising the following steps, performed in the orderlisted: providing a substrate; forming a PMOS gate on said substrate;forming PLDD regions in said substrate adjacent to said PMOS gate;forming PMOS gate sidewall spacers on lateral surfaces of said PMOSgate; ion implanting PSD regions in said substrate adjacent to said PMOSgate sidewall spacers with a first set of p-type dopants and a firstcarbon species; and performing a PSD UHT anneal on said PSD regions at atemperature above 1200 C for a time duration between 50 microseconds and100 milliseconds.
 10. The method of claim 9, in which a radiant powersource used in said PSD UHT anneal is a laser.
 11. The method of claim9, in which a radiant power source used in said PSD UHT anneal is aflash illuminator.
 12. The method of claim 9, in which said step ofperforming a PSD UHT anneal reduces a density of dislocation in spacecharge regions of said PSD regions below 100 dislocations/cm².
 13. Themethod of claim 12, in which said step of forming PLDD regions furthercomprises the following steps, performed in the order listed: ionimplanting said PLDD regions with a pre-amorphization implant (PAI) anda second carbon species; and performing a PLDD ultra high temperature(UHT) anneal on said PLDD regions at a temperature above 1200 C for atime duration between 50 microseconds and 100 milliseconds.
 14. Themethod of claim 13, in which said PAI further comprises implantingindium at a dose between 1·10¹³ and 5·10¹⁴ atoms/cm².
 15. The method ofclaim 14, in which said step of performing a PLDD UHT anneal reduces adensity of dislocation in space charge regions of said PLDD regionsbelow 100 dislocations/cm².
 16. The method of claim 15, furthercomprising the steps of; forming metal silicide layers on top surfacesof said PSD regions; forming a pre-metal dielectric (PMD) liner on topsurfaces of said metal silicide layers; forming a PMD layer on a topsurface of said PMD liner; forming contacts in said PMD and said PMDliner which make electrical connections with said metal silicide layers;forming an IMD layer on a top surface of said PMD; and forming a set ofmetal interconnects in said IMD layer which make electrical connectionsto said contacts.